• 대한화학회지
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• 제55권3호
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• pp.463-471
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• 2011

[ $N_2O_2$ ] 시프염기 리간드인 N,N'-bis(4-methoxysalicylidene) phenylendiamine(4-$CH_3O$-salphen)을 합성하였다. 분광광도법으로 4-$CH_3O$-salphen을 이용하여 수용액 중의 Fe(II)와 Fe(III)이온의 분리 정량실험을 위하여, 리간드 농도는 $4.0{\times}10^{-4}\;M$, DMF 용매와 물의 비율은 70/30(v/v), pH는 3.4~3.8 범위, 온도는 $55^{\circ}C$에서 1 시간 정도를 물 중탕하여 결과를 얻었다. 시료의 예비 산화 및 환원 전처리는 $5.0{\times}10^{-4}\;M$ 농도의 $H_2O_2$와 $NH_2OH{\cdot}HCl$을 사용하여 단일 원자가 상태의 시료를 만들어 사용하였다. 이때 Fe(II)와 Fe(III) 이온의 정량은 434 nm와 456 nm에서 흡광도를 측정하였다. 이상의 최적화된 실험조건을 이용하여 약수, 온천수, 바닷물 및 하수 처리장의 처리수를 채취하여 Fe(II)와 Fe(III) 이온을 각각 정량 분석한 결과는 측정 평균값이 표준 값에 대하여 2.00~6.90% 범위에서 잘 일치 하였고, 정량검출한계는 Fe(II)의 경우 27.9 ng/mL이었고, Fe(III)은 55.8 ng/mL이었다.

• International Journal of Safety
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• 제6권2호
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• pp.8-12
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• 2007

This study includes a case study among plastic process manufacturing companies, based on which, the currently used 4M method is applied in terms of machine, media, man, and management, to conduct quantitative risk evaluation, and thus to contribute to reducing human and material loss as well as preventing accidents in industrial fields. The result of this study is analyzed based on the 4M-risk assessment to find out the hazardous risk elements, and the quantitative evaluation made it predictable the value of risk(frequency $\times$ intensity) in such classified levels as serious risk, critical risk, and intolerable risk. Further, Among the businesses with hazardous risk elements and high frequency of industrial disaster, risk analysis was conducted for each process, and as a result, 38 cases among 76, including those of serious risk, critical risk, and intolerable risk, were improved, and the risk was reduced. Besides, it is thought that with the engineering approach with 4M-Risk Assessment, the attempt to improve safety level contributes to prevention of accidents.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.54-58
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• 2002

This paper describes the theoretical analysis and performance of a 2.4㎓ bulk-driven downconversion mixer, where the LO signal is input via the bulk. A mixer core designed with a 0.18$\mu\textrm{m}$ CMOS process is able to operate under 0.8V∼1V supply voltage. The RF, LO, and IF port frequencies are 2.45㎓, 2.4㎓, and 50MHz, respectively. The measurement results exhibit conversion gain of -1.8㏈, l㏈ compression point of -17㏈m and IIP3 of -4㏈m with 0㏈m LO power. The power consumption is as small as 4mW.

• Annals of Clinical Neurophysiology
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• 제25권2호
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• pp.84-92
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• 2023

Background: Clinical spectrum of immunoglobulin M (IgM) monoclonal gammopathy varies from IgM monoclonal gammopathy of unknown significance (IgM-MGUS) to hematological malignancies. We evaluated the clinical features, electrophysiological characteristics, and prognosis of patients with peripheral neuropathy associated with IgM monoclonal gammopathy (PN-IgM MG). Methods: We retrospectively evaluated 25 patients with PN-IgM MG. Peripheral neuropathy was classified as axonal, demyelinating, or undetermined, based on electrophysiological studies. We classified the enrolled patients into the IgM-MGUS and malignancy groups, and compared the clinical and electrophysiological features between the groups. Results: Fifteen patients had IgM-MGUS and 10 had hematologic malignancies (Waldenström's macroglobulinemia: two and B-cell non-Hodgkin's lymphoma: eight). In the electrophysiological evaluation, the nerve conduction study (NCS) criteria for demyelination were met in 86.7% of the IgM-MGUS group and 10.0% of the malignancy group. In particular, the distal latencies of the motor NCS in the IgM-MGUS group were significantly prolonged compared to those in the malignancy group (median, 9.1 ± 5.1 [IgM-MGUS], 4.2 ± 1.3 [malignancy], p = 0.003; ulnar, 5.4 ± 1.9 [IgM-MGUS], 2.9 ± 0.9 [malignancy], p = 0.001; fibular, 9.3 ± 5.1 [IgM-MGUS], 3.8 ± 0.3 [malignancy], p = 0.01; P-posterior tibial, 8.3 ± 5.4 [IgM-MGUS], 4.4 ± 1.0 [malignancy], p = 0.04). Overall treatment responses were significantly worse in the malignancy group than in the IgM-MGUS group (p = 0.004), and the modified Rankin Scale score at the last visit was higher in the malignancy group than in the IgM-MGUS group (2.0 ± 1.1 [IgM-MGUS], 4.2 ± 1.7 [malignancy], p = 0.001), although there was no significant difference at the initial assessment. Conclusions: The risk of hematological malignancy should be carefully assessed in patients with PN-IgM MG without electrophysiological demyelination features.

• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.117-125
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• 2007

This study proposes a CFD(Computational Fluid Dynamics) analysis as a method of verification of the designed-data and a supplement of the insufficient experiences in geothermal system, which shows a rapid growth among the renewable energies. The followings are the results. FLUENT 6.2.12 is used as a CFD tool on this study, with the equations of continuity, motion, energy for unsteady flow through pipes and k-epsilon turbulent model. S-type model which has one borehole with diameter 12m by depth 206m and T-type model which has 3 boreholes with $12m{\times}20m{\times}206m$ are proposed, and also the boundary conditions are described. The temperature differences between temperatures by CFD analysis and by on-site measurement are less than 1.5%, this shows a high reliability of CFD analysis process which this study proposes. After 11 days simulation operated 12 hours interval On/Off mode, it is clearly predicted that the outlet temperatures of geothermal pipes are increased by $1.2^{\circ}C$, and $2.2^{\circ}C$ after 4 months. And the outlet temperatures of geothermal pipes increased with increase of the mass flow rates through the pipes. T-type model shows that the 4m distance between boreholes are reasonable because the temperatures at 2m and 6m from boreholes are nearly same.

• 한국의류학회지
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• 제17권4호
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• pp.648-662
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• 1993

The summarized findings resulted from experiments and investigation are suggested as follows ; The analysis of measurements on the lower limb movements : For this experimentation, data was collected from three hundred and eighty female, age 19 to 23, who answered five lower limb movements(M1~M5). The statistics show that the order of the expansion ratio is gluteal area-length/knee-girth/back-line/knee-depth/thigh-depth/hip-girth, from the highest to the lowest in all movements. When comparing the correlation coefficient of the measurements, the values of the correlation coefficient of the height and the length items are very low, but those of the girth, the breadth, and the depth items are relatively high and those of the waist and the hip items are highest. For more sophisticated analysis, the factor analysis was conducted on the lower limb movements. Four factors were classified on the factor load by the "varimax rotation" method. Each movement shows the most important factor differently, as follows ; the most important factor in M1 is "the shape factor of lower limb below hip-line", that in M2 is "the cross-sectional shape factor", that in M3 is "the size factor of abdominal and loins region", and those in M4 and M5 accord with the interpretation of M3. When the investigation of the estimated function was conducted, in the selectional case of representative items on the slacks construction, it found that it would be better to add abdomen and thigh items as important considerations to waist girth, hip girth and crotch length.

• Natural Product Sciences
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• 제6권2호
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• pp.82-85
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• 2000

The aqueous ethanolic whole plant extract of Rosa arabica was found to contain the new natural dimeric phenolic compound, ellagic acid 3,3'-dimethyl ether $4-O-{\alpha}-rhamnopyranoside$, 9, along with ten known phenolic metabolites (1-8, 10 and 11). Structures of all compounds (1-11) were established by routine methods of analysis and confirmed by FAB-MS, $^1H\;and\;^{13}C$ NMR spectral analysis.

• 자원리싸이클링
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• 제20권2호
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• pp.67-73
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• 2011

연료전지 폐스택으로부터 백금을 회수하여 재사용하기 위하여 백금의 농도, pH, 환원제, 분산제의 영향을 살펴본 결과 1 mM $H_2PtCl_6$:10 mM $NaBH_4$:8 mM Cl4TABr = 1:0.4:0.4(vol.%), pH4, $50^{\circ}C$, 160 rpm, 10분 조건에서 최적 백금 나노 입자 제조 조건을 확립하였다. 시용 후 폐기된 MEA로부터 산침출을 통해 회수되어진 백금 침출 용액으로부터 백금 모사 용액과 동일한 조건에서 5 nm 이하의 백금 나노 입자를 합성하였다. 백금 모사 용액과 백금 침출 용액으로부터 합성된 백금 나노 입자를 XPS 분석을 통해 백금 이온에서 zero-valent의 백금 나노 입자로 환원되었음을 확인하였다.

• E2M - 전기 전자와 첨단 소재
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• 제4권3호
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• pp.249-258
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• 1991

He-Ne레이저(.lambda.=0.6328[.mu.m])를 광원으로 사용하는 y-cut LiNbO$_{3}$기판의 광 도파로 형성 과정을 빔 전송방식 메카니즘을 이용하여 광 도파로에서 광파의 전계 변화 및 전계 분포에 대하여 시뮬레이션 하였다. 그리고 Xl(55[.mu.m])* Zl(5000[.mu.m])인 LiNbO$_{3}$기판의 광 도파로 폭을 4[.mu.m], 버퍼층을 0.02[.mu.m]로 하였을때 도파로 층의 깊이가 0.2[.mu.m]인 지점에서 인가전압에 대한 x방향의 전계(E$_{x}$)와 y방향의 전계(E$_{y}$ )분포를 관찰하였다. 또한 단일 도파로의 파라미터 조건을 적용하여 X-스위치를 구성하였을때 전계를 인가하지 않은 상태에서 굴절율 변화(dn) 0.002, 도파로 폭(w) 3[.mu.m]로 하여 도파로의 교차각(.alpha.)을 0.4.deg.~0.6.deg.로 변화시킨 경우, .alpha.=0.5.deg.와 0.6.deg.일 때는 광빔이 bar측으로 출력되었고 .alpha.=0.4에서는 광빔이 cross측으로 출력 됨을 확인하였다. 따라서 위에서 확인된 도파로의 교차각 .alpha.=0.4.deg.인 경우, 전극간격(gap)이 2[.mu.m]인 조건에서 스위칭 전압을 인가하였을 때 25[V]에서 전기광학 효과에 의하여 광빔이 cross측에서 bar측으로 변조됨을 확인함으로써 X-스위치 광변조기의 기본적인 설계조건을 구현하였다.

• KSBB Journal
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• 제18권3호
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• pp.197-201
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• 2003

알콜증류 폐액에 빵효모를 배양하는 중에 포도당, 암모늄 및 인산을 자동 첨가하여 균체량을 효율적으로 증가시킴으로써 폐액의 재이용성을 향상시키고자 하였다. 포도당은 DO를 제어파라미터로 하는 제어방법을 사용하여 자동 첨가함으로서 그 농도를 300 mg/L 이하로 유지하였다. 암모늄은 pH-stat 방법을 사용하여 N $H_4$OH로서 자동 첨가함으로서 12.6~17.4mM의 낮은 농도범위로 유지하였다. 인산의 경우에는 분석방법으로써 ascorbic acid법을 채택한 자동화 FIA sysetm을 제작하여 사용하였다. 이 system으로 배양 19.4 시간 후부터 배양액을 자동분석하고 제어한 결과 배양액의 P $O_4$-P 농도를 23.3~43.4 mg/L 의 낮은 농도범위로 유지할 수 있었다. 세가지 영양성분을 자동첨가하면서 배양한 결과 증식의 정체없이 균체량을 33.0배 더 증가시킬 수 있었다. 비증식속도는 0.19 $hr^{－l}$였다.